With conventional loop-shaped electrodes comprising a thin wire with a diameter of typical up to 1 mm or a corresponding flat material, incision and surface coagulation effects utilized for stanching the blood of cut blood vessels occur depending on the type of current--cutting mode, coagulation mode, spray coagulation mode--of the employed high-frequency generator.
The kind of current influences the "processing result": dependent on the applied current, in addition to the cutting effect, surface coagulation is generated which permits stanching the bleeding of blood vessels running near the surface.
Large area ball or roller electrodes to which "coagulation current" is applied usually are used only for large-area stanching of blood as the final step of the surgical procedure.
As an alternative for high-frequency tissue removal, lasers can be employed for tissue ablation. Lasers suited for this purpose are substantially more expensive than high-frequency generators, therefore attempts have been made to find ways to also be able to remove adinomatous tissue as bloodlessly as possible using a high-frequency generator.
A number of authors have suggested using conventional monopolar electrodes with a cylindrical roll. Reference is made to U.S. Pat. No. 5,395,363. The surface of the cylindrical roll can be designed in a variety of ways: rolls with smooth surfaces, with grooved surfaces or with pointed surfaces are known. However, using high-frequency electrodes with rolls has the drawback that the relatively large roll impedes the surgeon's vision. Secondly, it is only possible in practice to vaporize the tissue with such type rolls by supplying higher high-frequency power, efficiency being unsatisfactory. This means the patient is not only exposed to very high current flow respectively high energy, which involves potential risk, for considerable time, but also the narcosis time is distinctly longer than in other surgical techniques.
Cutting loop electrodes are also known. Reference is made to U.S. Pat. No. 5,569,244. Conventional cutting loops typically employ a single flat lower surface. By flat is meant that a plane P would intersect the loop lower surface S in a line L. In other words, as viewed from the side (see FIG. 5), or in cross section the loop exhibits a flat lower surface S. A drawback exists with this design in that a trailing edge E of the flat lower surface may increase irritation of the coagulated tissue.